Antimicrobial activity of polysiloxane coatings containing quaternary ammonium-functionalized polyhedral oligomeric silsesquioxane / Partha Majumdar in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 7, N° 4 (07/2010)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 7, N° 4 (07/2010) . - p. 455-467 Titre : Antimicrobial activity of polysiloxane coatings containing quaternary ammonium-functionalized polyhedral oligomeric silsesquioxane Type de document : texte imprimé Auteurs : Partha Majumdar, Auteur ; Jie He, Auteur ; Elizabeth Lee, Auteur ; Alekhya Kallam, Auteur ; Nathan Gubbins, Auteur ; Shane J. Stafslien, Auteur ; Justin W. Daniels, Auteur ; Bret J. Chisholm, Auteur Année de publication : 2010 Article en page(s) : p. 455-467 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens Polydiméthylsiloxane Le polydiméthylsiloxane —[O-Si(CH3)2]n—, ou poly(diméthylsiloxane) selon la nomenclature systématique, communément appelé PDMS ou diméthicone, est un polymère organominéral de la famille des siloxanes souvent présent dans les shampoings. On l'y ajoute pour augmenter le volume des cheveux mais il peut également aller boucher les pores du cuir chevelu et rendre les cheveux gras. C'est une des raisons pour lesquelles se laver les cheveux tous les jours est très déconseillé avec un shampooing contenant des silicones. Il existe également de l'amodiméthicone, qui est un dérivé du diméthicone. Le polydiméthylsiloxane est un additif alimentaire (E900), utilisé comme antimoussant dans les boissons (Coca-Cola BlāK). La chaîne de poly(diméthylsiloxane) forme également la structure de base des huiles et des caoutchoucs silicones. Revêtements Silicones Les silicones, ou polysiloxanes, sont des composés inorganiques formés d'une chaine silicium-oxygène (...-Si-O-Si-O-Si-O-...) sur laquelle des groupes se fixent, sur les atomes de silicium. Certains groupes organiques peuvent être utilisés pour relier entre elles plusieurs de ces chaines (...-Si-O-...). Le type le plus courant est le poly(diméthylsiloxane) linéaire ou PDMS. Le second groupe en importance de matériaux en silicone est celui des résines de silicone, formées par des oligosiloxanes ramifiés ou en forme de cage (wiki). Silsesquioxanes oligomères polyhèdres Index. décimale : 667.9 Revêtements et enduits Résumé : An array of quaternary ammonium functionalized-polyhedral oligomeric silsesquioxane (Q-POSS) compounds with different alkyl chain lengths and counter ions were synthesized using a two-step process. First, octasilane POSS was functionalized with dimethylamino groups by hydrosilylation with allyldimethylamine. Next, partial quaternization of the tertiaryamino-functional POSS was achieved using an alkyl halide to produce the Q-POSS. Alkyl chain length of the Q-POSS compounds varied from –C12H25 to –C18H37 and the counter ions varied between chlorine, bromine, and iodine. Moisture-cured polysiloxane coatings were prepared by dispersing Q-POSS molecules into a solution blend of silanol-terminated polydimethylsiloxane, methylacetoxysilane, and a catalyst. To evaluate the utility of the Q-POSS molecules as a broad-spectrum antimicrobial additive, the antimicrobial activity of the coatings toward the Gram-negative bacterium, Escherichia coli, the Gram-positive bacterium, Staphylococcus aureus, and the opportunistic fungal pathogen, Candida albicans, was determined using an agar plating method. The results obtained showed that both the composition of the Q-POSS and the composition of the polysiloxane matrix affected antimicrobial properties. Compositions were identified that inhibited the growth of all three microorganisms on the coating surface. Surface Raman spectroscopic analysis was performed on selected set of coatings to understand the relative concentration of Q-POSS molecules at the coating surface. DOI : 10.1007/s11998-009-9197-x En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-009-9197-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9768 [article]

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ASTM accelerated dirt pickup resistance method with correlation to natural outsdoor weathering / Keith Alderfer in COATINGS TECH, Vol. 19, N° 6 (07/2022)  

[article]  inCOATINGS TECH > Vol. 19, N° 6 (07/2022) . - p. 38-47 Titre : ASTM accelerated dirt pickup resistance method with correlation to natural outsdoor weathering Type de document : texte imprimé Auteurs : Keith Alderfer, Auteur ; James Maher, Auteur ; Partha Majumdar, Auteur ; Jeff Sweeney, Auteur Année de publication : 2022 Article en page(s) : p. 38-47 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Essais accélérés (technologie) Peinture -- Normalisation Résistance à la salissure Résistance aux conditions climatiques Revêtements en bâtiment:Peinture en bâtiment Index. décimale : 667.9 Revêtements et enduits Résumé : The Architectural Subcommittee of ASTM’s Paint and Related Coatings, Materials and Applications Committee (D01.42), in collaboration with industrial partners, investigated an accelerated laboratory method to assess the exterior dirt pickup resistance of architectural coatings. A concurrent exterior exposure study was conducted with seven commercial paints across seven locations with varied climates throughout the United States for 36 months. The accelerated laboratory method explored multiple variables including dry time of the coating and QUV exposure time. For the exterior study, to understand the impact of multiple variables and their interactions on final response, a robust statistical methodology was applied utilizing both a mixed model with fixed and random effects to account for repeated measure analysis and a standard least square linear regression. Finally, the results from the two methods, laboratory and exterior, were compared to understand the similarity of the overall trends. Note de contenu : - EXPERIMENTAL : Materials - TEST PROCEDURES : Accelerated lab DPUR method - Natural weathering of paints for assessment of DPUR - RESULTS AND DISCUSSION : Results of accelerated DPUR single lab study - Results and analysis of exterior weathering DPUR study - Data analysis/modeling - CORRELATION OF PROPOSED ACCELERATED METHOD WITH EXTERIOR EXPOSURE : Mixed model approach for RMA - Table 1 : Description of paints used in the study - Table 2 : Results of accelerated lab DPUR method by paint ID, sheen category, and quality category En ligne : https://drive.google.com/file/d/1o34aGmHLfPF0iufRg-pHqlLFbpKgxIbr/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38225 [article]

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Big data comes to coatings / Partha Majumdar in EUROPEAN COATINGS JOURNAL (ECJ), N° 11 (11/2021)  

[article]  inEUROPEAN COATINGS JOURNAL (ECJ) > N° 11 (11/2021) . - p. 40-47 Titre : Big data comes to coatings : Novel formulation optimisation using big data, modelling, and predictive tools Type de document : texte imprimé Auteurs : Partha Majumdar, Auteur ; Jonathan DeRocher, Auteur ; Michael Tran, Auteur ; Nipun Bisht, Auteur ; Rose Bohling, Auteur ; Adeline Ossola, Auteur ; Ivan Boronat Monfort, Auteur ; Philip Harsh, Auteur ; James Bohling, Auteur ; Jeff Sweeney, Auteur Année de publication : 2021 Article en page(s) : p. 40-47 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agent mattant Analyse des données Données massives Essais (technologie) Formulation (Génie chimique) Modélisation prédictive Plan d'expérience Revêtements organiques Index. décimale : 667.9 Revêtements et enduits Résumé : Big data analytics and machine learning (ML) have disrupted nearly every industry, and are now being embraced by the coatings sector, whose formulations offer an almost infinite formulation landscape. This paper reviews recent work in this area, explores the use of iterative experimental design to map the performance of a matting resin and discusses the use of advanced data analysis through the application of applying various algorithms. Note de contenu : - EXPERIMENTAL : Materials - FORMULATIONS - TEST METHODS : Block - Tack - Coefficient of friction - Scrub - Stain - OUTLINE OF DESIGN OF EXPERIMENTS (DOE) - DATA ANALYSIS AND MODELS - OPTIMISATION - MODEL DEPLOYMENT - Fig. 1 :Distribution of gloss, scrub, and scatter plot of gloss vs. scrub with CoF overlay - Fig. 2 : Plots of LSMeans for comparing the impact of matting additives on (a) scrub and (b) CoF in white base, no extender formulations and the impact of both matting additives and extenders on (c) scrub and (d) CoF in white base with extender formulations - Fig. 3 : Plots of LSMeans for comparing the impact of matting agents on (a) tack, (b) CoF, and (c) scrub in deep base, no extender formulations - Fig. 4 : Plots of LSMeans for comparing the impact of interactions between matting agents and extenders on (a) tack, (D) CoF, and (c) scrub in deep base with extender formulations - Fig. 5 : Expansion of initial input parameters from material type to characteristic properties - Fig. 6 : Optimised formulation maps (a) all properties are equally important and (b) gloss, scrub, and CoF are twice as important as AKU and stain - Fig. 7 : Interactive formulation map implemented in Plotly Dash and deployed in RStudio - Table 1 : Typical white base formulations - Table 2 : Typical deep base formulation - Table 3 : Design variables including ingredient types and levels of interest - Table 4 : Model R2 values of key paint properties - Table 5 : Training and Test R2 values for the combined white base data set comparing methodologies applied to model paint properties using material property input parameters En ligne : https://drive.google.com/file/d/1jepJbW7hRp6AOq_tJ4cjI3SSB2OMKBfh/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36482 [article]

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Development of environmentally friendly, antifouling coatings based on tethered quaternary ammonium salts in a crosslinked polydimethylsiloxane matrix / Partha Majumdar in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 5, N° 4 (12/2008)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 5, N° 4 (12/2008) . - p. 405-417 Titre : Development of environmentally friendly, antifouling coatings based on tethered quaternary ammonium salts in a crosslinked polydimethylsiloxane matrix Type de document : texte imprimé Auteurs : Partha Majumdar, Auteur ; Bret J. Chisholm, Auteur ; Justin W. Daniels, Auteur ; Shane J. Stafslien, Auteur ; Nehal Patel, Auteur ; Elizabeth Lee, Auteur Année de publication : 2008 Article en page(s) : p. 405-417 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Ammoniums quaternaires -- Composés Polysiloxanes Revêtements antisalissures:Peinture antisalissures Index. décimale : 667.9 Revêtements et enduits Résumé : The concept of tethering quaternary ammonium salts (QASs) to a crosslinked polysiloxane matrix to produce a hybrid antifouling/fouling-release coating was investigated. A statistical experimental design was used to determine the effect of QAS concentration on biocidal activity toward a marine bacterium, Cellulophaga lytica (C. lytica). In addition to measuring biocidal activity, coating film quality as well as stability upon water immersion were evaluated. The results of the study showed that biocidal activity was strongly dependent on QAS concentration. For addition-curable coatings, the presence of 4 wt% QAS moieties resulted in approximately 50% reduction in C. lytica biofilm retention without any leachate toxicity. Attempts to increase the level of QAS moieties to increase biocidal activity resulted in coating delamination from the substrate and unacceptable film quality upon artificial seawater immersion due to excessive swelling. As a result, a moisture-curable system based on tethered QASs was investigated since moisture curing allows for higher crosslink densities to be achieved which would be expected to minimize swelling upon artificial seawater immersion. The moisture-curable coating developed showed enhanced stability upon artificial seawater immersion, greater than 80% reduction in C. lytica biofilm retention, and greater than 90% reduction in biofilm growth for the marine algae, Navicula incerta. DOI : 10.1007/s11998-008-9098-4 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-008-9098-4.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3466 [article]

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Fast-moving solutions / Bret J. Chisholm in EUROPEAN COATINGS JOURNAL (ECJ), N° 11/2008 (11/2008)  

[article]  inEUROPEAN COATINGS JOURNAL (ECJ) > N° 11/2008 (11/2008) . - p. 32-37 Titre : Fast-moving solutions : Automated processes speed up development of marine antifouling coatings Type de document : texte imprimé Auteurs : Bret J. Chisholm, Auteur ; Shane J. Stafslien, Auteur ; Partha Majumdar, Auteur ; Dean C. Webster, Auteur Année de publication : 2008 Article en page(s) : p. 32-37 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Animaux marins Lixiviation Marines (peinture) Revêtements antisalissures:Peinture antisalissures Salissures marines Index. décimale : 667.9 Revêtements et enduits Résumé : A combinatorial workflow has been developed to rapidly characterise both antifouling and fouling-release properties of marine coatings. Rapid automated methods exist for all aspects of coating research from experimental design through to data analysis. A key component is a set of biological tests using live marine organisms. Note de contenu : - Combinatorial workflow uses several distinct processes - Coating solutions are mixed automatically - Three application procedures - Surface energy and viscoelasticity profiling - Barnacle adhesion simulated with epoxy adhesive - Live marine organisms are also used in fouling tests - Leaching procedure validates long-term effectiveness - Antifouling and fouling release measured separately - Adhesion of live barnacle is also determined - Optimised coatings prepared for full-scale testing En ligne : https://drive.google.com/file/d/1H2lEK0fNof6_wFlxE9q6GotSyU5UV-na/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24141 [article]

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Flawless finish - Now with greater resistance / Partha Majumdar in EUROPEAN COATINGS JOURNAL (ECJ), N° 1 (01/2020)  

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High throughput combinatorial characterization of thermosetting siloxane-urethane coatings having spontaneously formed microtopographical surfaces / Partha Majumdar in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 4, N° 2 (06/2007)  

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The utilization of specific interactions to enhance the mechanical properties of polysiloxane coatings / Partha Majumdar in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 7, N° 2 (03/2010)  

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